This research program is aimed at understanding the regulation of expression of viral and cellular genes in normal and transformed cells, as well as the mechanisms by which viral or altered cellular gene expression leads to alterations of growth behavior. The project consists of seven parts: 1. The study of the control of gene expression in normal and polyoma virus transformed cells. 2. The study of the mechanisms regulating gene expression during the cell cycle and in response to growth factors. 3. The study of the biochemical properties and functions of the p53 cellular protein, which is induced in a variety of transformed cells. 4. The study of the rearrangements of the c-myc and c-myb proto oncogenes in human neoplasias and of the effects of such rearrangements on the expression of these genes. 5. The molecular and cytogenetic analysis of murine lymphomas induced by radiation and chemical carcinogens, with emphasis on the cellular oncogenes which are activated in this process. 6. The study of the role of human papilloma viruses in neoplastic lesions of the genital area, and of the expression of these viral genomes in tumors and in vitro. 7. The role of RNA helix destabilizing proteins in the process of transcription of eukaryotic genes.